Electric switch and condenser



Oct. 27, 1931. 3, E, JANSSQN 1,828,840

ELECTRIC SWITCH AND CONDENSER Filed Ma 21, 1928 26 /2-' 241 i 1 II I? 2-- j Fig. 1.

Patented Oct. 27, 1931 UNITED STATES PATENT OFFICE GUSTAV E. JANSSON. OF WOLLASTON, MASSACHUSETTS, ASSIGNOB T0 CONDIT ELEG- TBICAL MANUFACTURING'CORPORATION, OF SOUTH BOSTON, MASSACHUSETTS, A

CORPORATION 01 MASSACHUSETTS ELECTRIC SWITCH AND CONDENSER Application filed May 21,

This invention relates to electric switches and particularly to synchronizing switches whic are adapted to connect together two separately. energized sections of a hi h tension alternating current line when t e two sections are in synchronism with'each other.

One of the ob]ects of the present invention is the provision of an oil immersed electric switchwhich has high tensioncondensers associated with the terminals of the switch and immersed in andelectrically insulated by the oil surrounding the switchterminals and connected directly to the lower ends, or con tact members, of the switch, for thepurpose of reducing the voltage of a surge on the line and also for protecting the insulated terminalsof the switch from surge potentials that may be set up due to the operation of the switch. r i

A- further object of the invention-is generally to improve the construction of electric switches. I

Fig. 1 is a side elevationpartly broken away of an oil immersed electric switch embodying the invention. l I

.Fig. 2 is a section along the line 2-2 of Fig. 3 is a diagram. of the circuit connections of the switch, the condensers thereof and a synchronism indicator arranged to indicate the synchronic condition of the two sections of the switch circuit.

The electric switch embodying the present invention comprises a casing which includes the oil receptacle 10 and a switch frame 12 which comprises thecover for the oilreceptacle. Switch terminals including insulating bushings 14 are carried by the casing and depend therebelow into the oil-in the oil receptacle 10. Studs 16 are extend-edthrough said bushings and are provided with contact members 18 at their lower ends. Said contact members are bridged and electrically connected by a movable switch member 20. The switch so far described is more or less common in the art.

In T accordance with this invention, high tensionelectric condensers are provided each associated with a separate one ofthe switch terminals, and particularly with the contact Serial No. 279,406.

ternally corrugated to reduce the surface leakage between its ends. A cover plate 2 1 is secured to the top of the shell and is connected r-emovably with adepending bracket 26 carried by the switch frame 12. forms a closure for the lower end of the shell. A plurality of condenser elements 30 are disposed in series within said shell 22. Each condenser element may include a metal enclosing casing which forms one of the terminals of the condenser. An insulating bushing 32 extends above the casing and is provided with a terminal 34 which comprises the other terminal of the condenser. The

condenser elements are arranged one on top of the other so that the insulated terminal 34 of one condenser is connected electrically with the bottom of theouter casing of the next upper condenser element. The top condenser element is connected electrically with the cover plate 24 and the casing of the lowermost condenser is connected electrically with the cap 28.

The insulating shell 22 is completely immersed in the oil of the oil receptacle 10 and suitable openings, as the openings 36, in the cap 28 are provided to maintain a body of oil in the said shell and around the condenser elements'therein whereby to provide for the insulation of said elements. .VVith this arrangement, the dimensions of the condenser can be materially reduced over that necessary if a solid insulating compound were required, thus permitting the condensers to be installed within the casing of the oil switch where they are protected from mechanical damage. With this arrangement, also, no care need be taken to make the shell and its covers oil tight. Preferably the oil openings 36 are small in cross section so that carbon or other impurities in oil are prevented from passing into the interior of the condenser shell.

The cap 28"of each condenser shell is provided with a terminal 38. and said terminals are connected by conductors 40 each with a A cap 28.

separate one of the contact members 18. The lower terminals of the condensers are approximately at the level of the contact members and as close thereto as is practicable so that the condensers can receive the full value of any surge potential that may be set up due to the opening of the switch and thus reduce the value of the peak potential of the surge and protect the insulated terminals of the switch.

Each condenser is provided with one or more intermediate taps 41, 42 which are connected 'ith insulated bushin s 44 carried by the cover plate 1% and extended through openings in the supporting bracket 26. Said taps are connected with intermediate terminals of the condenser elements and thus provide reduced potentials which are proportional to the line potential for the purpose of operating s uichronism indicators and other low power consuming devices auxiliary to the line.

In Fig. 3, the connections between a synchronism indicator 46. the condensers and the switch are illustrated for the purpose of determining when the sections a. and b of the line are in synchronism, thus to indicate the proper time to close the switch. The high tension terminals of the synchronism indicator are connected across the taps 40 of the two condensers and thus are supplied with a potential which is the potential across the uppermost condenser elements of the condenser.

The low potential terminals are connected electrically with each other through the switch frame 12 and also usually to the ground through the usual ground connector not shown which is attached to the switch casing.

The above described arrangement of apparatus and condensers is efi ective in protecting such electrical apparatus as transformers and the like connected to the insulated terminals l l against harm due to abnormal potentials.

I claim:

1. A high tension electric switch compris ing an oil containing-enclosing casing. stationary switch members carried by said casing and having their lower ends immersed in the oil therein, said stationary switch members each consisting of an insulating bushing having a contact member at its lower end, a movable switch member cooperating with said contact members, and high tension electric condensers carried by said casing and immersed in the oil therein and having their high tension terminals under the oil adjacent and connected directly to said contact members and having their low tension terminals connected electrically with said casing, said condensers each having an insulated intermediate terminal which supplies a potential that is less than that of the high tension terminal.

2. An electric switch comprising an oil containing-enclosing casing, switch terminals carried by said casing and immersed in the oil therein, an electric condenser immersed in the oil in said casing and having its high tension terminal under the oil and, connected directly with one of said switch terminals under the oil and its low tension terminal connected with said casing, said condenser comprising an insulating enclosing shell which is open to the oil in said casing and having condenser elements located within said shell and surrounded and insulated by the oil therein.

3. A high tension electric switch having an oil containing enclosing casing comprising an oil receptacle and a cover therefor, insulated switch terminals carried by said cover and depending into the oil of said oil receptacle, and a high tension electric condenser carried by said cover and immersed in the oil therein having a low tension terminal at its upper end which is connected with said cover and a high tension terminal at its lower end which is connected with one of said switch terminals under said oil, said condenser comprising an insulating shell which is open to the oil in said receptacle and condenser elements located within said shell and surrounded and insulated by the oil therein.

4. A high tension electric switch comprising a cylindrical enclosing casing consisting of a cylindrical oil receptacle, and a circular.

able switch member cooperating with said,

contact members, and high tension electric condensers carried by said cover on opposite sides of the plane including said insulated terminals and each located adjacent one of said terminals, said condensers being immersed in the oil of said receptacle and having upper low tension terminals which are connected with said cover and having lower high tension terminals which are each connected directly with the contact member of the switch terminal to which it is adjacent, said condensers each comprising an insulating shell which is open to the oil in said receptacle and condenser elements located within said shell and immersed in and surrounded and insulated by the oil in said shell.

5. Electric switch apparatus for connecting two line sections when they are in synchronism comprising a switch having an oilcontaining, enclosing casing, switch terminals each connected to a separate line section and having contacts whichare immersed in the oil, a movable switch member for bridging said contacts, and condensers located within said casing and depending from the top thereof into the oil and having their lower ends terminated adjacent said contacts, high-tension terminals at the lower ends of said condensers having connections under the oil each with a separate contact, groundtension terminals at the upper ends of said condenser having connections with said casing, and low-tension intermediate terminals for connection with a synchronism indicating apparatus, the potential of which low-tension terminals vary in accordance with variation of potential of said contact.

In testimony whereof, I have signed my name to this specification.

GUSTAV E. J ANSSON. 

